CDL Blog

As operators look to maximize returns on their existing properties, or to invest in new opportunities, they often look “uphole” to shallower productive zones. The Upper Cretaceous Dunvegan Formation fits that bill in the Deep Basin of west-central Alberta. The Dunvegan was deposited in a fluvial-deltaic environment (figure 1) on the scale of the present day Mississippi Delta. Figure 2 is a cross-section that traverses one of the Dunvegan delta’s larger distributary channels and shows the facies complexities of the formation.

Hydrodynamics plays an important role in the Dunvegan in the review area as the Deep Basin transitions downdip from conventional reservoirs where water is the continuous fluid phase to reservoirs that are lower-pressured or higher-pressured with respect to the regional system and where hydrocarbons are generally the continuous fluid phase (CDL, 2020). An IP90 bubble map for Dunvegan producers spudded since 2010 shows that that there is generally more water produced in the conventional system vs the Deep Basin system (figure 1) as predicted by the conventional to Deep Basin model described above.

Canadian Discovery Ltd. (CDL) recently updated its hydrodynamics maps for the Dunvegan. The varying pressure regimes:

• Have a predictable impact on hydrocarbons-in-place
• The low-pressured Deep Basin hosts most of the oil producers that have little or no water production
• The high-pressured Deep Basin hosts most of the big gas (and condensate) producers, also with little or no water production.
• The conventional system is characterized mostly by oil wells that also produce hefty amounts of water
• Have a massive impact on water risk
• Correlate strongly to liquids yields.

Figures 3a and 3b show IP90 rates for oil and BOE for the companies that have put wells on-stream since the start of 2018. CNRL leads the way, followed by Mancal, Cequence, Tangle Creek and Whitecap. IP90 oil rates range up to 600 bopd, with the average being around 150 to 200 bopd. The areas are lined up to match the regional cross-section and the wells are symbolized by operator. The difference between the two graphs indicates the amount of gas in BOE that was produced. Kakwa, in the high pressure Deep Basin regime, and Karr, which straddles the high and low pressure Deep Basin regimes, have the biggest gas producers led by Strath and Tourmaline.

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CDL’s recently updated Dunvegan hydrodynamics data, maps and graphs are useful tools for mitigating risk and predicting hydrocarbon phase windows in these uncertain times.

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